import java.io.*;
import java.util.*;
public class Main {
	public static void main(String[] args) {
		String s="";
		File b[]=null;
		int i;
		Scanner a=new Scanner(System.in);
		s=a.nextLine();
		File f=new File(s);
		b=f.listFiles();
		System.out.println(b.length);
		for(i=0;i<b.length;i++)
			System.out.println(b[i].getName());
	}
}